This post was last modified: 2021-10-23, 18:32 by brian_in_the_cloud.

Gunther,

Does LRTimelapse support more than 2 circular gradients across an image sequence?

I'm using LRTimelapse 5.6.3 (build 717) on macOS 11.4.

When I add more than two circular gradients to the first key frame of a sequence, and then synchronize these gradients across all keyframes, only the first two show up in LRT, and the others remain unchanged across all images.

Is this a known limitation?

I checked the FAQ and couldn't find anything about this.

I first ran into this when processing a stream of 2247 images of 42 megapixels each last night.

This morning I went through and tried this with a shorter fresh stream of smaller images and ran into exactly the same situation.

When I dig into the image properties menu in LRT for the first image of this sequence I see crs:CircularGradientBasedCorrections with all of my gradients listed beneath, so it's confusing to me why LRTimelapse doesn't use them all.

Thanks,
Brian

LRTimelapse supports 4 linear and 2 circular gradients. You need to use the ones that LRTimelapse creates on initialization. You cannot add or delete gradients. Any additional gradients won't be animated.

Thanks for your reply. Is there a technical reason for this? This seems like a pointless limitation from my perspective. I know java well and this is likely just a memory limitation, that could be controlled in preferences somehow. My machine has 128G of ram, so I can afford to allocate more to the LRT JVM.

This post was last modified: 2021-10-24, 01:08 by Gunther.

Yes it is a technical limitation. It has nothing to do with java but with the way Lightroom works. There is a limited set of parameters that are meant to be animated. Those Gradients get predefined and every additional gradient will slow down the processing even for sequences that don't use them. That's why the set of gradients is a compromise between flexibility and processing speed. If not encountered one single timelapse that I could not edit with the given tools.
But of course you are free to file a feature request in the feature request forum.

I did notice that LRT is creating gradients when I'm not using them. If possible, that seems like a good performance improvement to avoid doing.

If LRT is creating 4 linear and 2 circular gradients for every single sequence, and that's slowing down people who don't use any gradients in a sequence, then having a user controllable parameter to adjust this could both speed people up and enable more functionality.

FYI, the sequence where I want three circular gradients is an overnight time-lapse from near death valley in california. There is light pollution from both Las Vegas and Las Angeles on the horizon, and I have a circular gradient for each of those to suppress it somewhat. I then also wanted to adjust the galactic center as well, and that's where I ran into this limitation. For now I'm simply doing two passes with LRT and TIFF -> DNG for the second round, and that will allow me to apply more than three circular gradients in total, but is going to make it take a LOT longer.

I'll file a feature request later today related to this. I'm a software developer so expect it to be somewhat detailed.

Thanks,
Brian

A few questions before I submit a more formal feature request:

Where are these gradients predefined?

Is there some reason that all sequences need to have 4 linear and 2 circular gradients defined by LRT even if no gradient processing is used for that sequence? From your message above it sounds like that is slowing down processing when not using the gradients.

I'd like to propose some kind of ability to change this 4 linear / 2 circular limitation, but would like a few quick answers before writing more than this:

1. Is it possible to allow a particular user to set a preference for each of these values that would apply to all of their image sequences that they process?
2. is it possible to allow this user to change these values for specific image sequences?
3. Can LRT detect these numbers from the first keyframe and then proceed?

Sorry, but currently there is no way to have the Gradients treated dynamically. Trust me, if it was, I would already have implemented it.
For your scenario there are a couple of things you could do, for example use a simple brush stroke with a large paintbrush and apply your edits to that one.
When using a Paintbrush, note that only the settings on the first stroke will be animated, the position cannot be animated. Also keep the stroke as simple as you can - long strokes can exceed the capacity of the XMP files and break them.

You could also try to add one or more additional circular gradient to the very first keyframe at the begin of your editing, then sync only the circ. grdients to all frames (also the non keyframes) - then you will have 3 circulars on the whole sequence, from which only the first 2 will be animated by LRT. But the third will be there with static settings.

To be honest, you don't need to file the feature request about having Gradients being treated dynamically - I of course have that in my mind and if I ever see a way to do it, I certainly will. But there are so many complications involved when it comes to that in a timelapse scenario...

Tomorrow Adobe will release LR 11 with the new Masiking and I will release LR 5.7. This will change a lot in this regards and lift some limitations. But still for now, you will have the static number of gradients that can be animated.

If you would like to explain the limitations more to me I would like to help you figure out a better path. I don't expect or have time to look at the code, but I'd like to help here if possible.